A scheme of optical four-level pulse amplitude modulation(PAM-4) is proposed based on dual-Raman process in Rydberg atoms. A probe field counter-propagates with a dual-Raman field which drives the ground and the excit...A scheme of optical four-level pulse amplitude modulation(PAM-4) is proposed based on dual-Raman process in Rydberg atoms. A probe field counter-propagates with a dual-Raman field which drives the ground and the excited states transition, respectively, and the Rydberg transition is driven by a microwave(MW) field. A gain peak appears in the probe transmission and is sensitive to the MW field strength. Optical PAM-4 can be achieved by encoding an MW signal and decoding the magnitude of a probe signal. Simulation results show that the differential nonlinearity and the integral nonlinearity of the proposed scheme can be reduced by 5 times and 6 times, respectively, compared with the counterparts of previous scheme, and the ratio of level separation mismatch is close to the ideal value 1. Moreover, the scheme is extended to optical PAM-8 signal, which may further improve the spectral efficiency.展开更多
The rapid advancement of technology and the increasing demand for high- performance computing have fueled the development of faster and more efficient interconnects. Among these, the Peripheral Component Interconnect ...The rapid advancement of technology and the increasing demand for high- performance computing have fueled the development of faster and more efficient interconnects. Among these, the Peripheral Component Interconnect Express (PCIe) standard has emerged as a dominant interface in modern computing systems. This paper provides a detailed technical analysis of the evolution from PCIe to the latest PCIe 6 standards, highlighting the key enhancements, architectural changes, performance improvements, and potential applications. Through an in-depth examination of the PCIe 6 specification, we explore the implications and benefits of this new interface technology, paving the way for future innovations in data transfer and interconnectivity. The analysis of PCIe to PCIe 6, a next-generation interface evolution, has revealed significant advancements and improvements in terms of bandwidth, performance, latency, and scalability. PCIe 6 offers a doubling of the bandwidth compared to its predecessor, PCIe 5, providing higher data transfer rates and increased throughput. Overall, the analysis reveals that PCIe 6 represents a significant advancement in interconnect technology, offering improved performance, enhanced features, and expanded capabilities.展开更多
We report 20 Gb/s transmission of four-level pulse amplitude modulation （PAM） signal using a directly modulated tunable distributed Bragg reflector （DBR） laser. Transmission distance over 20 km was achieved withou...We report 20 Gb/s transmission of four-level pulse amplitude modulation （PAM） signal using a directly modulated tunable distributed Bragg reflector （DBR） laser. Transmission distance over 20 km was achieved without using optical amplifiers and optical dispersion compensation modules. A wavelength tuning range of 11.5 nm and a 3 dB bandwidth greater than 10 GHz over the entire wavelength tuning range were obtained.展开更多
In this Letter, we have proposed a generalized Gaussian probability density function（GGPDF）-based method to estimate the symbol error ratio（SER） for pulse amplitude modulation（PAM-4） in an intensity modulation/d...In this Letter, we have proposed a generalized Gaussian probability density function（GGPDF）-based method to estimate the symbol error ratio（SER） for pulse amplitude modulation（PAM-4） in an intensity modulation/direct detection（IM/DD） system. Furthermore, a closed form expression of SERGGDfor PAM-4 has been derived. The performance of the proposed method is evaluated through simulation as well as experimental work.The fitting of probability density functions of the received signal is applied via GGPDF and shape parameters P1 and P2 associated with different PAM-4 levels are determined. The optimum single value of shape parameter P is then calculated to estimate the SER. The mathematical relationship of P with different received optical powers and receiver bandwidths has been determined and verified. The proposed method is a fast and accurate method to estimate SER of a PAM-4 system, which is more reliable and in agreement with the error counting method.展开更多
In this paper,an optical pulse amplitude modulation with 4 levels(PAM-4)using a fiber combiner is proposed to enhance the data rate of a field-programmable gate-array-based long-distance real-time underwater wireless ...In this paper,an optical pulse amplitude modulation with 4 levels(PAM-4)using a fiber combiner is proposed to enhance the data rate of a field-programmable gate-array-based long-distance real-time underwater wireless optical communication system.Two on-off keying signals with different amplitudes are used to modulate two pigtailed laser diodes,respectively,and the generated optical signals are superimposed into optical PAM-4 signals by a fiber combiner.The optical PAM-4scheme can effectively alleviate the nonlinearity,although it reduces the peak-to-peak value of the emitting optical power by 25%.A real-time data rate of 187.5 Mbit/s is achieved by using the optical PAM-4 with a transmission distance of 50 m.The data rate is increased by about 25%compared with the conventional electrical PAM-4 in the same condition.展开更多
基金Project supported by the Shandong Natural Science Foundation,China (Grant No. ZR2021LLZ006)the National Natural Science Foundation of China (Grant Nos. 61675118 and 12274123)+1 种基金the Taishan Scholars Program of Shandong Province,China (Grant No. ts20190936)the Shandong University of Science and Technology Research Fund,China(Grant No. 2015TDJH102)。
文摘A scheme of optical four-level pulse amplitude modulation(PAM-4) is proposed based on dual-Raman process in Rydberg atoms. A probe field counter-propagates with a dual-Raman field which drives the ground and the excited states transition, respectively, and the Rydberg transition is driven by a microwave(MW) field. A gain peak appears in the probe transmission and is sensitive to the MW field strength. Optical PAM-4 can be achieved by encoding an MW signal and decoding the magnitude of a probe signal. Simulation results show that the differential nonlinearity and the integral nonlinearity of the proposed scheme can be reduced by 5 times and 6 times, respectively, compared with the counterparts of previous scheme, and the ratio of level separation mismatch is close to the ideal value 1. Moreover, the scheme is extended to optical PAM-8 signal, which may further improve the spectral efficiency.
文摘The rapid advancement of technology and the increasing demand for high- performance computing have fueled the development of faster and more efficient interconnects. Among these, the Peripheral Component Interconnect Express (PCIe) standard has emerged as a dominant interface in modern computing systems. This paper provides a detailed technical analysis of the evolution from PCIe to the latest PCIe 6 standards, highlighting the key enhancements, architectural changes, performance improvements, and potential applications. Through an in-depth examination of the PCIe 6 specification, we explore the implications and benefits of this new interface technology, paving the way for future innovations in data transfer and interconnectivity. The analysis of PCIe to PCIe 6, a next-generation interface evolution, has revealed significant advancements and improvements in terms of bandwidth, performance, latency, and scalability. PCIe 6 offers a doubling of the bandwidth compared to its predecessor, PCIe 5, providing higher data transfer rates and increased throughput. Overall, the analysis reveals that PCIe 6 represents a significant advancement in interconnect technology, offering improved performance, enhanced features, and expanded capabilities.
基金supported by the National Key Research and Development Program of China(Nos.2016YFB0402301 and 2017YFF0206103)the National Natural Science Foundation of China(Nos.61320106013,61635010,61474112,61574137,and 61504170)
文摘We report 20 Gb/s transmission of four-level pulse amplitude modulation （PAM） signal using a directly modulated tunable distributed Bragg reflector （DBR） laser. Transmission distance over 20 km was achieved without using optical amplifiers and optical dispersion compensation modules. A wavelength tuning range of 11.5 nm and a 3 dB bandwidth greater than 10 GHz over the entire wavelength tuning range were obtained.
文摘In this Letter, we have proposed a generalized Gaussian probability density function（GGPDF）-based method to estimate the symbol error ratio（SER） for pulse amplitude modulation（PAM-4） in an intensity modulation/direct detection（IM/DD） system. Furthermore, a closed form expression of SERGGDfor PAM-4 has been derived. The performance of the proposed method is evaluated through simulation as well as experimental work.The fitting of probability density functions of the received signal is applied via GGPDF and shape parameters P1 and P2 associated with different PAM-4 levels are determined. The optimum single value of shape parameter P is then calculated to estimate the SER. The mathematical relationship of P with different received optical powers and receiver bandwidths has been determined and verified. The proposed method is a fast and accurate method to estimate SER of a PAM-4 system, which is more reliable and in agreement with the error counting method.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61971378)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA22030208)Zhoushan-Zhejiang University Joint Research Project(No.2019C81081)。
文摘In this paper,an optical pulse amplitude modulation with 4 levels(PAM-4)using a fiber combiner is proposed to enhance the data rate of a field-programmable gate-array-based long-distance real-time underwater wireless optical communication system.Two on-off keying signals with different amplitudes are used to modulate two pigtailed laser diodes,respectively,and the generated optical signals are superimposed into optical PAM-4 signals by a fiber combiner.The optical PAM-4scheme can effectively alleviate the nonlinearity,although it reduces the peak-to-peak value of the emitting optical power by 25%.A real-time data rate of 187.5 Mbit/s is achieved by using the optical PAM-4 with a transmission distance of 50 m.The data rate is increased by about 25%compared with the conventional electrical PAM-4 in the same condition.
